Gone are the days when you'd choose diesel purely to save money. The diesel-powered BMW 640d is the most exciting 6 Series you can buy - until the M6 arrives in any case. It works particularly well in M Sport guise.

Inside & Out: 4/5

If you're going to buy a BMW 6 Series, then you have to opt for the M Sport package. There's not much wrong with the standard car, but the upgrade really enhances the car's lines and adds tastier alloys - though beware that the rims pictured on the test car were optional 20-inch items.

While the M Sport look suggests that the 6 Series is an out-and-out sports car, the cabin reveals its alter ego - that of a luxury cruiser. It builds on the interior of the latest 5 Series with its own unique shape, dominated by the huge display screen and wide transmission tunnel. There's precious little rear leg room, but nobody buys a car like this expecting anything more. In contrast, the boot is big. Most impressive though is the quality. Every surface is covered either in leather or tactile, textured plastic.

Ride & Handling: 4/5

Bear in mind that the 6 Series is no lightweight. Yet it manages to shrug off its weight with a chassis that deals even with crappy Irish road surfaces. Admittedly it's best not to use the firmest of the damper settings, but even on large alloys it copes pretty well. More importantly, it's fun to drive when you have an interesting road in front of you. That said, it's best suited to wide, sweeping roads than tight and twisty back lanes, though more because of its width than anything else. Needless to say there's loads of grip from the huge tyres, but the traction control light flashes regularly if you're pushing on in the wet. Thankfully the electronic nannies help rather than hinder progress. Saying all that, it's not a car designed for regular track use. The brakes and tyres would soon wilt.

Engine & Transmission: 5/5

We can't think of a single thing we don't like about this engine-gearbox combo. Die-hard enthusiasts may lament the proliferation of diesel power - and the automatic gearbox for that matter - but actual buyers of this type of car will relish the effortless performance and relaxing nature of the transmission. In any case, if you really want to take control, the paddles behind the steering wheel allow you to. With so much torque available there's little reason to extend the six-cylinder turbodiesel to the redline. Though it's creamy smooth when you do - and it even sounds good.

Equipment, Economy & Value for Money: 3.5/5

There aren't many buyers of €100,000 coupés around right now, but those that are know what they want and while the BMW may theoretically compete against Jaguar, Mercedes and Porsche alternatives we reckon buyers will have a preference before they start looking at the equipment list. For the record, some of the options on our test car were eye wateringly expensive, such as €5,151 for Adaptive Drive. It's generously specified as standard. However, we do reckon the M Sport model is worth the hefty €7,000 premium over the SE model.

Running costs are reduced by the fact that emissions mean the 640d is only in Band C for annual road tax and the combined consumption figure is an impressive 5.5 litres/100km.